Effectiveness of Pfizer-BioNTech mRNA Vaccination Against COVID-19 Hospitalization Among Persons Aged 12-18 Years - United States, June-September 2021

Efficacy, Effectiveness, and Safety of COVID-19 Vaccine Compared to Placebo in Preventing COVID-19 Infection among 12-17 Years Old: A Systematic Review

Objectives

The World Health Organization recently revised their recommendations and considered healthy children and adolescents as low priority group for COVID-19 vaccine. This review comprehensively assessed existing clinical evidence on COVID-19 vaccine in 12-17 years old.

Methods

Included in this review were any type of study that investigated the efficacy, immunogenicity, safety, and effectiveness of COVID-19 vaccine on protection against SARS-COV-2 infection in 12-17 years old. Various electronic databases were searched up to March 15, 2023. Studies were screened, data extracted, risk of bias appraised, and certainty of evidence was judged using GRADE. Review Manager 5.4 was used to estimate pooled effects. Difference between the two groups was described as mean difference for continuous variables and as relative risk or odds ratio for categorical variables.

Results

There were six randomized controlled trials and 16 effectiveness studies (8 cohorts and 8 case control). Low certainty evidence showed that BNT162b2 (Pfizer) was effective, immunogenic, and safe in healthy adolescents. There were 15 effectiveness studies on BNT162b2 (Pfizer) in healthy adolescent and one on immunocompromised patients. It was protective against infection with any of the variants, with higher protection against Delta than Omicron. BNT162b2 is protective against hospitalization and emergency and urgent care (high certainty); and critical care and MIS-C (low). Very low certainty evidence noted that BNT 162b2 was also immunogenic in 12-21 years old with rheumatic diseases while on immunomodulatory treatment but with possible increased exacerbation of illness. Low certainty evidence demonstrated that mRNA-1273 (Moderna) was effective, immunogenic, and safe. Low to very low certainty evidence were noted on the safety and immunogenicity of two vector base vaccines (ChAdOx1-19 and Ad5 vector COVID vaccine) and two inactivated vaccines (CoronaVac and BBIBP CorV).

CONCLUSION

There is presently low certainty evidence on the use of RNA vaccines in 12-17 years old. The recommendation on its use is weak. There is presently insufficient evidence for the use of inactivated and vector-based COVID-19 vaccines. Different countries should consider whether to vaccinate healthy adolescent without comprising the other recommended immunization and health priorities that are crucial for this age group. Other factors including cost-effectiveness of vaccination and disease burden should be accounted.

Effectiveness of COVID-19 vaccination against school absenteeism in children and adolescents hospitalized with COVID-19

BACKGROUND

COVID-19 vaccination has been recommended for children to protect them and to enable in-person educational and social activities.

METHODS

We estimated COVID-19 vaccination effectiveness (VE) against school absenteeism in children 5-17 years old hospitalized from September 1, 2021 through May 31, 2023. Full vaccination was defined as two vaccine doses.

RESULTS

We studied 231 children admitted to hospital with COVID-19, including 206 (89.2 %) unvaccinated/partially vaccinated and 25 (10.8 %) fully vaccinated. Unvaccinated/partially vaccinated children were absent from school for longer periods compared to fully vaccinated children (median absence: 14 versus 10 days; p-value = 0.05). Multivariable regression showed that full COVID-19 vaccination was associated with fewer days of absence compared to no/partial vaccination on average (adjusted relative risk: 0.77; 95 % CI: 0.61 to 0.98). COVID-19 VE was 50.7 % (95 % CI: -11.3 % to 78.2 %) for school absenteeism above the median duration of absenteeism.

CONCLUSIONS

Full COVID-19 vaccination conferred protection against school absenteeism in hospitalized school-aged children with COVID-19.

An overview of the COVID-19 pediatric vaccine program - The U.S. experience vaccinating children ages 6 months through 17 years

COVID-19 vaccination decreases risk for COVID-19 illness and severe disease in children, including multisystem inflammatory syndrome (MIS-C) and death. On December 13, 2020, CDC recommended COVID-19 vaccination for persons ages ≥16 years, with expansion on May 12, 2021, to adolescents ages 12-15 years; to children ages 5-11 years on November 2, 2021; and to children ages 6 months-4 years on June 18, 2022. Following each age-specific recommendation, the U.S. government collaborated with state and local governments, vaccine manufacturers, and numerous other public and private entities, to ensure rapid, broad, and equitable COVID-19 vaccine distribution to strategic locations across the country to maximize access. However, vaccination coverage among children has been lower than among adults and lower among younger children than adolescents. As of May 10, 2023, COVID-19 primary series vaccination coverage was 61.8% among U.S. children ages 12-17 years, 32.9% among those ages 5-11 years, and 5.5% among those ages 6 months-4 years. This manuscript describes the planning and implementation of the U.S. COVID-19 pediatric vaccine program, including successes (e.g., the availability of pharmacy vaccination to extend access beyond more traditional pediatric vaccine providers) and challenges (e.g., multi-dose vaccine vials instead of single-dose vials, leading to concerns about wastage) to provide a historical record of the program and to help inform planning and implementation of future routine or pandemic-related pediatric vaccination campaigns.

Geospatially clustered low COVID-19 vaccine rates among adolescents in socially vulnerable US counties

COVID-19 vaccinations are widely available across the United States (U.S.), yet little is known about the spatial clustering of COVID-19 vaccinations. This study aimed to test for geospatial clustering of COVID-19 vaccine rates among adolescents aged 12-17 across the U.S. counties and to compare these clustering patterns by sociodemographic characteristics. County-level data on COVID-19 vaccinations and sociodemographic characteristics were obtained from the COVID-19 Community Profile Report up to April 14, 2022. A total of 3,108 counties were included in the analysis. Global Moran's I statistic and Anselin Local Moran's analysis were used, and clustering patterns were compared to sociodemographic variables using t-tests. Counties with low COVID-19 vaccinated clusters were more likely, when compared to unclustered counties, to have higher numbers of individuals in poverty and uninsured individuals, and higher values of Social Vulnerability Index (SVI) and COVID-19 Community Vulnerability Index (CCVI). While high COVID-19 vaccinated clusters, compared to neighboring counties, had lower numbers of Black population, individuals in poverty, and uninsured individuals, and lower values of SVI and CCVI, but a higher number of Hispanic population. This study emphasizes the importance of addressing systemic barriers, such as poverty and lack of health insurance, which were found to be associated with low COVID-19 vaccination coverage.

Building the U.S. COVID-19 vaccine effectiveness program: Past successes and future directions

COVID-19 vaccines were originally authorized in the United States in December 2020 on the basis of safety, immunogenicity, and clinical efficacy data from randomized controlled trials (RCTs). However, real-world vaccine effectiveness (VE) data are necessary to provide information on how the vaccines work in populations not included in the RCTs (e.g., nursing home residents), against new SARS-CoV-2 variants, with increasing time since vaccination, and in populations with increasing levels of prior infection. The goal of CDC's COVID-19 VE program is to provide timely and robust data to support ongoing policy decisions and implementation of vaccination and includes VE platforms to study the spectrum of illness, from infection to critical illness. Challenges to estimating VE include accurate ascertainment of vaccination history, outcome status, changing rates of prior infection, emergence of new variants, and appropriate interpretation of absolute and relative VE measures. CDC COVID-19 VE platforms have played a pivotal role in numerous vaccine policy decisions since 2021 and will continue to play a key role in future decisions as the vaccine program moves from an emergency response to a routine schedule.

Detection and Characterization of Web-Based Pediatric COVID-19 Vaccine Discussions and Racial and Ethnic Minority Topics: Retrospective Analysis of Twitter Data

Background

Despite pediatric populations representing a smaller proportion of COVID-19 cases and having a less severe prognosis, those belonging to racial and ethnic minority groups are at an increased risk of developing more severe COVID-19-related outcomes. Vaccine coverage is crucial to pandemic mitigation efforts, yet since the start of the COVID-19 pandemic, vaccine hesitancy has increased and routine pediatric immunizations have decreased. Limited research exists on how vaccine hesitancy may contribute to low pediatric COVID-19 vaccine uptake among racial and ethnic minority populations.

Objective

This study aimed to characterize COVID-19 vaccine-related discussion and sentiment among Twitter users, particularly among racial and ethnic minority users.

Methods

We used the Twitter application programming interface to collect tweets and replies. Tweets were selected by filtering for keywords associated with COVID-19 vaccines and pediatric-related terms. From this corpus of tweets, we used the Biterm Topic Model to output topics and examined the top 200 retweeted tweets that were coded for pediatric COVID-19 vaccine relevance. Relevant tweets were analyzed using an inductive coding approach to characterize pediatric COVID-19 vaccine-related themes. Replies to relevant tweets were collected and coded. User metadata were assessed for self-reporting of race or ethnic group affiliation and verified account status.

Results

A total of 863,007 tweets were collected from October 2020 to October 2021. After outputting Biterm Topic Model topics and reviewing the 200 most retweeted tweets, 208,666 tweets and 3905 replies were identified as being pediatric COVID-19 vaccine related. The majority (150,262/208,666, 72.01%) of tweets expressed vaccine-related concerns. Among tweets discussing vaccine confidence, user replies expressing agreement were significantly outweighed by those expressing disagreement (1016/3106, 32.71% vs 2090/3106, 67.29%; P<.001). The main themes identified in the Twitter interactions were conversations regarding vaccine-related concerns including adverse side effects, concerns that the vaccine is experimental or needs more testing and should not be tested on pediatric populations, the perception that the vaccine is unnecessary given the perceived low risk of pediatric infection, and conversations associated with vaccine-related confidence (ie, the vaccine is protective). Among signal tweets and replies, we identified 418 users who self-identified as a racial minority individual and 40 who self-identified as an ethnic minority individual. Among the subcodes identified in this study, the vaccine being protective was the most discussed topic by racial and ethnic minority groups (305/444, 68.7%).

Conclusions

Vaccine-related concerns can have negative consequences on vaccine uptake and participation in vaccine-related clinical trials. This can impact the uptake and development of safe and effective vaccines, especially among racial and ethnic minority populations.

Safety and Efficacy of a Third Dose of the BNT162b2 Vaccine in Liver-Transplanted and Healthy Adolescents

Objectives

According to our previous study, the 2-dose-BNT162b2 vaccination is less effective against the Omicron variant. This study aimed to assess the safety and efficacy of a 3-dose-BNT162b2 vaccination in liver-transplanted (LT) and healthy adolescents.

Methods

LT and healthy adolescents who met the inclusion criteria received a third dose of the BNT162b2 vaccine (30 µg). Antireceptor-binding domain immunoglobulin and T-cell-specific responses to severe acute respiratory syndrome coronavirus 2 spike peptides were assessed 3 months before the third dose (Visit -1) and 0 (Visit 0), 1 (Visit 1), and 2 months (Visit 2) after the third dose. Antinucleocapsid immunoglobulin and neutralizing antibodies were assessed at Visits 0 and 1. Adverse events (AEs) were monitored.

Results

Eleven LT and 14 healthy adolescents aged 14.64 (13.2, 15.7) years (44.2% male) had antireceptor-binding domain immunoglobulin geometric mean titers of 1412.47 (95% confidence interval [CI], 948.18-2041.11) and 1235.79 (95% CI, 901.07-1705.73) U/mL at Visit -1 but increased to 38 587.76 (95% CI, 24 628.03-60 460.18) and 29 222.38 (95% CI, 16 291.72-52 401.03) U/mL (P < 0.05) at Visit 1, respectively. This was consistent with neutralizing antibodies (42.29% and 95.37% vs 44.65% and 91.68%, P < 0.001) and interferon-γ-secreting cells in LT and healthy adolescents at Visit 0 versus Visit 1, respectively. For serious AEs, an LT girl with autoimmune overlap syndrome died 5 months postvaccination from acute liver failure.

Conclusions

In both LT and healthy adolescents, humoral and cellular immune responses were high after the 3-dose-BNT162b2 vaccination. However, serious AEs were suspected in LT adolescents with autoimmune diseases.

Characteristics and management of patients with SARS-CoV2 infection admitted to pediatric intensive care units: Data analysis of the Spanish national multicenter registry

INTRODUCTION

The purpose of this study is to describe the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV2) disease characteristics and management in children admitted to the pediatric intensive care units (PICU).

METHODS

The present study was based on a national multicentric prospective registry including PICU patients with SARS-CoV2 infection or symptoms of multisystem inflammatory syndrome in children (MIS-C).

RESULTS

A total of 298 patients were admitted to 41 different Spanish PICUs. A total of 76% of them were previously healthy. The most frequent manifestation was MIS-C (69.8%). On admission, 59.4% of patients did not have respiratory distress, and only 17.4% needed conventional mechanical ventilation (MV). The need for MV was associated with age (incidence rate ratios [IRR] 1.21, p < .012), pediatric sequential organ failure assessment score (p-SOFA) Score (IRR 1.12, p = .001), and need for transfusion (IRR 4.5, p < .004) in MIS-C patients, and with vasoactive drug use (IRR 2.73, p = .022) and the diagnosis of acute respiratory distress syndrome (IRR 2.83, p = .018) in patients admitted for other reasons. During the first day of admission, 56% of patients met shock criteria and 50.7% needed vasoactive drugs. In MIS-C patients, their use was associated with higher p-SOFA score (IRR 1.06, p < .001) and with the diagnosis of shock (IRR 5.78, p < .001). In patients without MIS-C, it was associated with higher p-SOFA score (IRR 1.05, p = .022). The mortality rate was 3%, being lower in MIS-C patients compared to patients admitted for other reasons (0.5% vs. 9.4%, p < .001). It was also lower in previously healthy patients compared to patients with previous comorbidities (0.9% vs. 9.7%, p < .001).

CONCLUSIONS

Severe SARS-CoV2 infection is uncommon in the pediatric population. In our series, respiratory distress was rare, being MIS-C the most frequent cause of PICU admission related to SARS-CoV2. In most cases, the course of the disease was mild except in children with previous diseases.

Parental Perception and Barriers Regarding COVID-19 Vaccination in Technology Dependent Children

INTRODUCTION

Children who use chronic home mechanical ventilation are at high risk for respiratory infections and mortality. They are also at increased risk for developing severe COVID-19 infection. The primary goal of this study was to evaluate the parental perception of the COVID-19 vaccine in pediatric patients with technology dependence.

METHOD

We conducted a cross-sectional survey at a children's hospital between September 2021 and February 2022. A telephone or in-person interview was conducted to assesss parental attitudes toward the COVID-19 vaccine for their technology-dependent child. Technology-dependent groups included patients requiring (1) invasive mechanical ventilation via tracheostomy and (2) noninvasive mechanical ventilation via a facial interface.

RESULTS

Fourteen of 44 participants (32%) of technology-dependent children were vaccinated for COVID-19 despite high parental vaccination and influenza vaccination rates. Twenty-eight patients (63% of total participants) were tracheostomy dependent. In the tracheostomy group, the COVID-19 vaccine rate was 28% versus 54% in the nontracheostomy group.  Concern for vaccine side effects was the major reason for vaccine hesitancy (53%). More parents of vaccinated children than unvaccinated children were counseled by their primary care provider (85.7% vs. 46.7%; p = .02) or subspecialist (93% vs. 47%; p = .003).

CONCLUSIONS

Our findings suggest counseling by primary care providers and subspecialists is important in overcoming COVID-19 vaccine hesitancy. Social media was identified as a major source of information, particularly among parents of unvaccinated patients.

The role of vaccination route with an adenovirus-vectored vaccine in protection, viral control, and transmission in the SARS-CoV-2/K18-hACE2 mouse infection model

Introduction

Vaccination is the most effective mechanism to prevent severe COVID-19. However, breakthrough infections and subsequent transmission of SARS-CoV-2 remain a significant problem. Intranasal vaccination has the potential to be more effective in preventing disease and limiting transmission between individuals as it induces potent responses at mucosal sites.

Methods

Utilizing a replication-deficient adenovirus serotype 5-vectored vaccine expressing the SARS-CoV-2 RBD (AdCOVID) in homozygous and heterozygous transgenic K18-hACE2, we investigated the impact of the route of administration on vaccine immunogenicity, SARS-CoV-2 transmission, and survival.

Results

Mice vaccinated with AdCOVID via the intramuscular or intranasal route and subsequently challenged with SARS-CoV-2 showed that animals vaccinated intranasally had improved cellular and mucosal antibody responses. Additionally, intranasally vaccinated animals had significantly better viremic control, and protection from lethal infection compared to intramuscularly vaccinated animals. Notably, in a novel transmission model, intranasal vaccination reduced viral transmission to naïve co-housed mice compared to intramuscular vaccination.

Discussion

Our data provide convincing evidence for the use of intranasal vaccination in protecting against SARS-CoV-2 infection and transmission.

Optimizing COVID-19 Vaccination Strategy in Pediatric Kidney Transplant Recipients: Humoral and Cellular Response to SARS-CoV-2 mRNA Vaccination

In this retrospective cohort study, we analyze the early humoral and cellular response in 64 adolescents KTx recipients, after two or three doses of mRNA vaccine BNT162b2 against different variants of COVID-19. After 2 doses, 77.8% % of children with no history of infection had a positive humoral response with a median anti-S IgG level of 1107 (IQR, 593-2,658) BAU/mL. All the patients with a history of infection responded with a higher median IgG level (3,265 (IQR, 1,492-8,178) BAU/mL). In non-responders after 2 doses, 75% responded after a third dose with a median Ab titer at 355 (IQR, 140-3,865 BAU/mL). Neutralizing activity was significantly lower against the delta and the omicron variants compared to the wild-type strain and did not improve after a 3rd dose, while infection did provide higher levels of neutralizations against the variants. T cell specific response correlated with humoral response and no patient displayed a cellular response without a humoral response. Adolescent KTx recipients exhibit a high seroconversion rate after only two doses. A third injection, induces a response in the majority of the non-responders patients but did not counterbalance the strong decrease in neutralizing antibody activities against variants highlighting the need for boosters with specific vaccines.

Resource use and disease severity of children hospitalized for COVID-19 versus multisystem inflammatory syndrome in children (MIS-C) in Canada

Background

Direct comparisons of paediatric hospitalizations for acute coronavirus disease 2019 (COVID-19) and multisystem inflammatory syndrome in children (MIS-C) can inform health system planning. We describe the absolute and relative hospital burden of acute paediatric COVID-19 and MIS-C in Canada.

Methods

This national prospective study was conducted via the Canadian Paediatric Surveillance Program from March 2020-May 2021. Children younger than 18 years old and hospitalized for acute COVID-19 or MIS-C were included in the analysis. Outcomes included supplemental oxygen (low-flow oxygen or high-flow nasal cannula), ventilation (non-invasive or conventional mechanical), vasopressors, paediatric intensive care unit (PICU) admission, or death. Adjusted risk differences (aRD) and 95% confidence intervals (CI) were calculated to identify factors associated with each diagnosis.

Results

Overall, we identified 330 children hospitalized for acute COVID-19 (including five deaths) and 208 hospitalized for MIS-C (including zero deaths); PICU admission was required for 49.5% of MIS-C hospitalizations versus 18.2% of acute COVID-19 hospitalizations (aRD 20.3; 95% CI, 9.9-30.8). Resource use differed by age, with children younger than one year hospitalized more often for acute COVID-19 (aRD 43.4% versus MIS-C; 95% CI, 37.7-49.1) and more children 5-11 years hospitalized for MIS-C (aRD 38.9% vs. acute COVID-19; 95% CI, 31.0-46.9).

Conclusion

While there were more hospitalizations and deaths from acute paediatric COVID-19, MIS-C cases were more severe, requiring more intensive care and vasopressor support. Our findings suggest that both acute COVID-19 and MIS-C should be considered when assessing the overall burden of severe acute respiratory syndrome coronavirus 2 in hospitalized children.

Effectiveness of BNT162b2 vaccine against SARS-CoV-2 Delta and Omicron infection in adolescents, Norway, August 2021 to January 2022

OBJECTIVES

We estimated the BNT162b2 vaccine effectiveness (VE) against any (symptomatic or not) SARS-CoV-2 Delta and Omicron infection among adolescents (12-17-years-old) in Norway from August 2021 to January 2022.

METHODS

We used Cox proportional hazard models, where vaccine status was included as a time-varying covariate and models were adjusted for age, sex, comorbidities, residence county, birth country, and living conditions.

RESULTS

VE against Delta infection peaked at 68% (95%CI:64-71%) and 62% (95%CI:57-66%) in days 21-48 after the first dose among 12-15-year-olds and 16-17-year-olds respectively. Among 16-17-year-olds that received two doses, VE against Delta infection peaked at 93% (95%CI:90-95%) in days 35-62 and decreased to 84% (95%CI:76-89%) in ≥63 days after vaccination. We did not observe a protective effect against Omicron infection after receiving one dose. Among 16-17-year-olds, VE against Omicron infection peaked at 53% (95%CI:43-62%) in 7-34 days after the second dose and decreased to 23% (95%CI:3-40%) in ≥63 days after vaccination.

CONCLUSIONS

We found reduced protection after two BNT162b2 vaccine doses against any Omicron infection compared to Delta. Effectiveness decreased with time from vaccination for both variants. The impact of vaccination among adolescents on reducing infection and thus transmission is limited during Omicron dominance.

The impact of the COVID-19 pandemic on individuals with Fontan circulation: Focus on gaps in care

Background

Gaps in subspecialty cardiology care could potentially delay identification and care for multi-organ complications common in patients with Fontan circulation. This study analyzed the frequency of gaps in care for individuals with Fontan circulation during the COVID-19 pandemic and associated demographic and clinical factors.

Methods

This retrospective study evaluated individuals with Fontan circulation followed at our center since 2010. A gap in care was defined as an absence of any formal cardiology provider-patient contact (clinic visit or telehealth) for >15 months.

Results

Over a third of 308 patients with Fontan circulation experienced at least one gap in care between 2010 and 2022, and 77 experienced a gap in care during the COVID-19 pandemic. Of this latter group, 27 (35%) had never experienced a prior gap in cardiology care until the pandemic. Those who experienced gaps in care during the pandemic were on average older (18.0 [IQR 9.6-25.6] vs. 14.2 [7.2-21.2] years, p = 0.01), more likely to be of Black/African American race (23.4% vs 7.4%, p = 0.001), and less likely to have a diagnosis of protein-losing enteropathy or plastic bronchitis (0% vs. 8.6%, p = 0.005). Those without a gap in care during the pandemic were more likely to have utilized telehealth visits (13% vs 3%, p = 0.02).

Conclusion

Gaps in care are common and appear to have been exacerbated by the COVID-19 pandemic in those with a Fontan circulation. Such gaps are particularly common among African American and adult patients, and may potentially be mitigated by expanding telehealth access.

COVID-19 vaccination in children: a public health priority

OBJECTIVE

Covid-19 had a direct impact on children's health. The aim of this review was to analyze epidemiological and clinical data, the consequences of the pandemic, and vaccination aspects in this group.

SOURCES OF DATA

The searches were carried out from January 2020 to November 2022, in the MEDLINE databases (PubMed) and publications of the Brazilian Ministry of Health and the Brazilian Society of Pediatrics.

SUMMARY OF FINDINGS

Covid-19 has a mild presentation in most children; however, the infection can progress to the severe form and, in some cases, to MIS-C. The prevalence of the so-called long Covid in children was 25.24%. Moreover, several indirect impacts occurred on the health of children and adolescents. Vaccination played a crucial role in enabling the reduction of severe disease and mortality rates. Children and adolescents, as a special population, were excluded from the initial clinical trials and, therefore, vaccination was introduced later in this group. Despite its importance, there have been difficulties in the efficient implementation of vaccination in the pediatric population. The CoronaVac vaccines are authorized in Brazil for children over three years of age and the pediatric presentations of the Pfizer vaccine have shown significant effectiveness and safety.

CONCLUSIONS

Covid-19 in the pediatric age group was responsible for the illness and deaths of a significant number of children. For successful immunization, major barriers have to be overcome. Real-world data on the safety and efficacy of several pediatric vaccines is emphasized, and the authors need a uniform message about the importance of immunization for all children.

Anaphylaxis rates following mRNA COVID-19 vaccination in children and adolescents: Analysis of data reported to EudraVigilance

AIM

The present study aimed to estimate the anaphylaxis rates following mRNA COVID-19 vaccination in children and adolescents in Europe.

METHODS

We retrieved data on 371 anaphylaxis cases following mRNA COVID-19 vaccination in children ≤ 17 years old notified to EudraVigilance as of October 8, 2022. Overall, 27,120,512 doses of BNT162b2 vaccine and 1,400,300 doses of mRNA-1273 vaccine have been delivered to children during the study period.

RESULTS

The overall mean anaphylaxis rate was 12.81 [95% confidence interval (CI): 11.49-14.12] per 10⁶ mRNA vaccine doses [12.14 (95% CI: 6.37-17.91) per 10⁶ doses for mRNA-1273 and 12.84 (95% CI: 11.49-14.19) per 10⁶ doses for BNT162b2]. Children 12-17 years old accounted for 317 anaphylaxis cases, followed by 48 cases in children 3-11 years old, and 6 cases in children 0-2 years old. Children 10-17 years old had a mean anaphylaxis rate of 13.52 (95% CI: 12.03-15.00) cases per 10⁶ mRNA vaccine doses and children 5-9 years old had a mean anaphylaxis rate of 9.51 (95% CI: 6.82-12.20) cases per 10⁶ mRNA vaccine doses. There were two fatalities, both in the 12-17 years age group. The fatal anaphylaxis rate was 0.07 cases per 10⁶ mRNA vaccine doses.

CONCLUSIONS

Anaphylaxis is a rare adverse event after receiving an mRNA COVID-19 vaccine in children. Continuous surveillance of serious adverse events is needed to guide vaccination policies as we move towards SARS-CoV-2 endemicity. Larger real-world studies on COVID-19 vaccination in children, using clinical case confirmation, are imperative.

Effectiveness of primary series and booster vaccination against SARS-CoV-2 infection and hospitalisation among adolescents aged 12-17 years in Singapore: a national cohort study

BACKGROUND

Singapore offered the BNT162b2 vaccine (tozinameran; Pfizer-BioNTech) to adolescents aged 12-17 years in May 18, 2021, and extended booster vaccines to this group in Jan 21, 2022. Literature on the effectiveness of primary series and booster vaccination among adolescents is scarce outside of Europe and North America. We aimed to determine primary series and booster vaccine effectiveness against SARS-CoV-2 infection and hospitalisation among adolescents in Singapore.

METHODS

For this national cohort study, we assessed the incidence of confirmed SARS-CoV-2 infection and hospitalisation among adolescents aged 12-17 years vaccinated with BNT162b2 in Singapore from Sept 1 to Dec 15, 2021, during the delta (B.1.617.2) variant wave, and from Jan 21 to April 28, 2022, during the omicron (B.1.1.529) variant wave. Data were collected from official databases maintained by the Ministry of Health of Singapore. Individuals were classified as partly vaccinated (those who had received one dose and those who had received the second dose no more than 7 days previously), fully vaccinated (8 days after receiving a second dose), or boosted (8 days after receiving a third dose) and compared with unvaccinated individuals.

FINDINGS

249 763 individuals aged 12-17 years were included in the study, contributing over 56·2 million person-days of observation. Compared with unvaccinated individuals, two vaccine doses achieved vaccine effectiveness of 66% (95% CI 63-69) against infection with the delta variant and 25% (21-29) against infection with the omicron variant, and 83% (74-89) against delta variant-associated hospitalisation and 75% (56-86) against omicron variant-associated hospitalisation. Booster vaccination with a third dose achieved vaccine effectiveness of 56% (53-58) against infection with the omicron variant and 94% (86-97) against omicron-associated hospitalisation, compared with unvaccinated adolescents. Vaccine effectiveness against infection for both variants after two doses waned over time, whereas vaccine effectiveness against hospitalisation for both variants remained stable; both were increased after three doses.

INTERPRETATION

Among adolescents aged 12-17 years, vaccine effectiveness against confirmed SARS-CoV-2 infection after two doses of BNT162b2 decreased over time and increased after a third dose. Boosted adolescents were also the most protected from hospitalisation compared with fully vaccinated, partly vaccinated, and unvaccinated adolescents. Therefore, the booster dose of BNT162b2 can help to reduce the burden on the health-care system and individual morbidity during an omicron wave.

FUNDING

None.

COVID-19 Vaccines-All You Want to Know

The severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) pandemic has led to an unprecedented public health crisis. The collective global response has led to production of multiple safe and effective vaccines utilizing novel platforms to combat the virus that have propelled the field of vaccinology forward. Significant challenges to universal vaccine effectiveness remain, including immune evasion by SARS-CoV-2 variants, waning of immune response, inadequate knowledge of correlates of protection, and dosing in special populations. This review serves as a detailed evaluation of the development of the current SARS-CoV-2 vaccines, their effectiveness, and challenges to their deployment as a preventive tool.

Duration of immunity to SARS-CoV-2 in children after natural infection or vaccination in the omicron and pre-omicron era: A systematic review of clinical and immunological studies

Background

Duration of humoral and cellular memory in children previously infected SARS-CoV-2 or vaccinated and subsequent risk of reinfection is still not fully elucidated.

Methods

Systematic review of studies retrieved from medical databases and article reference lists.

Results

From 2420 identified articles, 24 met the inclusion criteria. Children infected during the pre-omicron era developed long lasting (at least 10-12 months) humoral and cellular immunity against pre-Omicron SARS-CoV-2 variants, but have reduced in vitro cross-reactivity against Omicron. Conversely, although vaccination has a limited efficacy in preventing new infection with pre-Omicron and Omicron variants, in vitro studies suggested that vaccine-induced immunity provides better in vitro cross-neutralization against pre-Omicron and Omicron variants. Preprints published after the period of inclusion of our review suggested that overall risk of infection after Omicron infection is reduced, but children developed weak neutralizing responses in about half cases.

Conclusions

Available evidence, although limited, suggested a long-lasting but unperfect protection of previous infections or vaccination against pre-Omicron and Omicron variants. Based on our findings, it might be reasonable to offer families of children infected before Omicron a booster vaccination. A similar indication should be proposed also for those infected with Omicron, specifically for more fragile children at higher risk of COVID-19-related complications, based on better cross-variant neutralisation induced by vaccination.

Systematic review registration

PROSPERO, identifier ID 353189.

Comparison of the Onset and End of Specific and Major Side Effects in Iranian Teenage Participants Vaccinated With COVID-19 Vaccine: Sinopharm and Soberana

Background

Clinical trials were conducted on children on side effects after vaccination. We tried to assess the frequency and onset of the main symptoms in children who were vaccinated. We aimed to evaluate early and delayed adverse effects after coronavirus disease 2019 (COVID-19) vaccine among Iranian pediatrics and adolescents in a national survey.

Methods

This cross-sectional study included people <18 years who received the Soberana (PastoCoVac) and Sinopharm vaccines since 2021. The basic information was gender, age, type of vaccine, and reaction after vaccination besides the main events that occurred for them. The required data were collected via a predetermined checklist by trained interviewers through phone calls by their parents or legal guardians. The independent t test and Fisher exact test were used. P values less than 0.05 were considered significant.

Results

A total of 11,042 participants (age range, 10-18 years) consisting of 5374 boys (47.8%) and 5768 girls (52.2%) were studied and 88.1% of the children (n = 9727) were vaccinated by Sinopharm and 11.9% (n = 1315) by Soberana. The data of kidney-related side effects had delayed improvement of side effects after the Sinopharm compared with the Soberana vaccines (P = 0.012). Cardiovascular and hematological side effects showed early-onset (P = 0.006) and delayed improvement of side effects (P = 0.002) after the Soberana vaccine compared with the Sinopharm vaccine. Neurological side effects showed delayed improvement of side effects after the Soberana vaccine compared with the Sinopharm vaccine (P = 0.027). Joint-related side effects showed early-onset (P = 0.004) and delayed improvement of side effects (P = 0.023) after the Soberana vaccine compared with the Sinopharm vaccine. Respiratory side effects showed delayed improvement of side effects after the Soberana vaccine compared with the Sinopharm vaccine (P = 0.013), and dermatological side effects showed early-onset (P = 0.050) and delayed improvement of side effects (P = 0.035) after the Soberana vaccine compared with the Sinopharm vaccine. There was not any statistically significant difference regarding gastrointestinal side effects between the 2 vaccines (P > 0.05).

Conclusion

The cardiovascular and hematological, joint-related (non-neurologic musculoskeletal) and dermatological side effects after the Soberana vaccine appear earlier and end later compared with the Sinopharm vaccine. Improvement of renal side effects in the Sinopharm vaccine group and improvement of neurological and respiratory side effects in the Soberana vaccine group occurred with delay compared with other vaccines.

Frequently Asked Questions on Coronavirus Disease 2019 Vaccination for Hematopoietic Cell Transplantation and Chimeric Antigen Receptor T-Cell Recipients From the American Society for Transplantation and Cellular Therapy and the American Society of Hematology

Coronavirus disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), disproportionately affects immunocompromised and elderly patients. Not only are hematopoietic cell transplantation (HCT) and chimeric antigen receptor (CAR) T-cell recipients at greater risk for severe COVID-19 and COVID-19-related complications, but they also may experience suboptimal immune responses to currently available COVID-19 vaccines. Optimizing the use, timing, and number of doses of the COVID-19 vaccines in these patients may provide better protection against SARS-CoV-2 infection and better outcomes after infection. To this end, current guidelines for COVID-19 vaccination in HCT and CAR T-cell recipients from the American Society of Transplantation and Cellular Therapy Transplant Infectious Disease Special Interest Group and the American Society of Hematology are provided in a frequently asked questions format.

Vaccinating Children against SARS-CoV-2: A Literature Review and Survey of International Experts to Assess Safety, Efficacy and Perceptions of Vaccine Use in Children

Introduction: The balance of risks and benefits of COVID-19 vaccination in children is more complex than in adults with limited paediatric data resulting in no global consensus on whether all healthy children should be vaccinated. We sought to assess the safety, efficacy, and effectiveness of childhood vaccination against SARS-CoV-2, as well as better understanding perceptions of vaccination in parents and vaccine experts. Methods: We performed a literature review for COVID-19 vaccine safety, efficacy, effectiveness, and perceptions. We searched international safety databases for safety data and developed an electronic survey to elicit country-specific COVID-19 immunisation data, including vaccine regulations, policies, rates, and public attitudes solicited from vaccine experts. Results: Nine studies were included in the final safety analysis. Local reactions were frequently reported across all studies and vaccine types. Adverse events reported to surveillance systems tended to be non-serious, and commonly included injection site reactions and dizziness. Twenty-three studies reported immunogenicity, efficacy, and effectiveness data. There were nine randomised control trials of six different vaccine types, which showed seroconversion of neutralising antibodies in vaccinated children ranging from 88% to 100%. The vaccine efficacy for Pfizer and Moderna vaccines ranged from 88% to 100%. There were 118 survey responses representing 55 different countries. Reported vaccination rates ranged from <1% to 98%. Most respondents described “mixed opinions” regarding paediatric vaccination policies in their country. By region, a more positive public attitude towards vaccination correlated with higher vaccination rates. Discussion: In this mixed-methods review, we have found evidence that vaccination against COVID-19 in children is safe, efficacious, and effective. Overall, the combined evidence from both the literature review and survey highlights the need for further data on both the safety and effectiveness of COVID-19 vaccinations in children.

BNT162b2 COVID-19 vaccination uptake, safety, effectiveness and waning in children and young people aged 12-17 years in Scotland

Background

The two-dose BNT162b2 (Pfizer-BioNTech) vaccine has demonstrated high efficacy against COVID-19 disease in clinical trials of children and young people (CYP). Consequently, we investigated the uptake, safety, effectiveness and waning of the protective effect of the BNT162b2 against symptomatic COVID-19 in CYP aged 12-17 years in Scotland.

Methods

The analysis of the vaccine uptake was based on information from the Turas Vaccination Management Tool, inclusive of Mar 1, 2022. Vaccine safety was evaluated using national data on hospital admissions and General Practice (GP) consultations, through a self-controlled case series (SCCS) design, investigating 17 health outcomes of interest. Vaccine effectiveness (VE) against symptomatic COVID-19 disease for Delta and Omicron variants was estimated using a test-negative design (TND) and S-gene status in a prospective cohort study using the Scotland-wide Early Pandemic Evaluation and Enhanced Surveillance of COVID-19 (EAVE II) surveillance platform. The waning of the VE following each dose of BNT162b2 was assessed using a matching process followed by conditional logistic regression.

Findings

Between Aug 6, 2021 and Mar 1, 2022, 75.9% of the 112,609 CYP aged 16-17 years received the first and 49.0% the second COVID-19 vaccine dose. Among 237,681 CYP aged 12-15 years, the uptake was 64.5% and 37.2%, respectively. For 12-17-year-olds, BNT162b2 showed an excellent safety record, with no increase in hospital stays following vaccination for any of the 17 investigated health outcomes. In the 16-17-year-old group, VE against symptomatic COVID-19 during the Delta period was 64.2% (95% confidence interval [CI] 59.2-68.5) at 2-5 weeks after the first dose and 95.6% (77.0-99.1) at 2-5 weeks after the second dose. The respective VEs against symptomatic COVID-19 in the Omicron period were 22.8% (95% CI -6.4-44.0) and 65.5% (95% CI 56.0-73.0). In children aged 12-15 years, VE against symptomatic COVID-19 during the Delta period was 65.4% (95% CI 61.5-68.8) at 2-5 weeks after the first dose, with no observed cases at 2-5 weeks after the second dose. The corresponding VE against symptomatic COVID-19 during the Omicron period were 30.2% (95% CI 18.4-40.3) and 81.2% (95% CI 77.7-84.2). The waning of the protective effect against the symptomatic disease began after five weeks post-first and post-second dose.

Interpretation

During the study period, uptake of BNT162b2 in Scotland has covered more than two-thirds of CYP aged 12-17 years with the first dose and about 40% with the second dose. We found no increased likelihood of admission to hospital with a range of health outcomes in the period after vaccination. Vaccination with both doses was associated with a substantial reduction in the risk of COVID-19 symptomatic disease during both the Delta and Omicron periods, but this protection began to wane after five weeks.

Funding

UK Research and Innovation (Medical Research Council); Research and Innovation Industrial Strategy Challenge Fund; Chief Scientist's Office of the Scottish Government; Health Data Research UK; National Core Studies - Data and Connectivity.

Cardiac Effects of COVID-19 Infection, MIS-C, and the Vaccine in Infants and Children: What Is Known and Future Implications

The cardiac effects of novel coronavirus disease 2019 (COVID-19) infection on the pediatric heart has become an area of particular interest as elevated cardiac enzymes and abnormalities on echocardiogram and electrocardiogram were seen in a portion of children affected by the virus. In this article, we review the cardiac manifestations of acute COVID-19 infection, multisystem inflammatory syndrome in children, and postvaccine myocarditis. The limited research on the effects of COVID-19 on neonates and infants is also reported. KEY POINTS: · Cardiac involvement from MIS-C is much higher than the risk of COVID-19 vaccine-induced myocarditis.. · Neonates and infants have overall been less affected by COVID-19 than adults and older children.. · At this point in time, there is limited research on the cardiac effects of COVID-19 in neonates..

COVID-19 Epidemiology, Immunity, and Vaccine Development in Children: A Review

Although pediatric populations experienced lower COVID-19 severity and mortality than adults, the epidemiology of this disease continues to evolve. COVID-19 clinical manifestations in pediatrics commonly include fever and cough, but may differ from adults and by variant. Serious complications, including MIS-C, rarely occur. Although early data showed a decreased likelihood of COVID-19 transmission from children versus adults, outbreaks and viral shedding studies support pediatric transmission potential. Children may mount more robust initial immune responses to SARS-CoV-2 versus adults. COVID-19 vaccines with available pediatric data include BNT162b2, mRNA-1273, CoronaVac, and BBIBP-CorV. Depending on age group and jurisdiction, BNT162b2 and mRNA-1273 have received full approval or emergency/conditional authorization in the United States and European Union from 6 months of age. Clinical trials have shown BNT162b2 and mRNA-1273 safety and high efficacy in pediatric populations, with demonstrably noninferior immune responses versus young adults. Real-world studies further support BNT162b2 safety and effectiveness against the Delta variant. mRNA vaccination benefits are considered to outweigh risks, including myocarditis; however, pediatric vaccination rates remain relatively low. Given a growing body of clinical trial and real-world data showing vaccine safety and effectiveness, pediatric vaccination should be prioritized as an important strategy to control the pandemic.

Effectiveness of the BNT162b2 (Pfizer-BioNTech) Vaccine in Children and Adolescents: A Systematic Review and Meta-Analysis

Efforts to control the COVID-19 pandemic have expanded to the vaccination of children and adolescents. This systematic review assesses the utility of the BNT162b2 (Pfizer-BioNTech) vaccine in children and adolescents aged 5-18 years, considering its effectiveness against COVID infection, hospital and intensive care admission and duration of effectiveness after vaccination. Six databases were searched following the PRISMA guidelines. Pooled estimates and 95% confidence intervals (CIs) were calculated using meta-analysis. Fifteen studies were included in the systematic review, while 12 studies were included in the meta-analysis. Evidence suggests that the two-dose vaccination regime provided high effectiveness of 92% (95% CI, 86-96) against COVID infection. Vaccination also conferred high protection against hospitalisation (91%) and intensive care admission (85%). The vaccine was highly protective against the Delta variant of the virus, but showed a lower protection against the Omicron variant. Most adverse effects were transient and mild, commonly including pain at the injection site, fatigue and headache. Current findings are suggestive of waning immunity over time; however, further research is needed to investigate the relevance of booster doses in this age group. In summary, the Pfizer-BioNTech BNT162b2 vaccine demonstrated high levels of protection against COVID-19 infection and its complications while maintaining an adequate safety profile in children and adolescents.

Factors Associated With COVID-19 Non-vaccination in Adolescents Hospitalized Without COVID-19

BACKGROUND

Pfizer-BioNTech COVID-19 vaccine received emergency use authorization for persons ≥ 16 years in December 2020 and for adolescents 12-15 years in May 2021. Despite the clear benefits and favorable safety profile, vaccine uptake in adolescents has been suboptimal. We sought to assess factors associated with COVID-19 non-vaccination in adolescents 12-18 years of age.

METHODS

Between June 1, 2021 and April 29, 2022, we assessed factors associated with COVID-19 non-vaccination in hospitalized adolescents ages 12-18 years enrolled in the Overcoming COVID-19 vaccine effectiveness network. Demographic characteristics and clinical information were captured through parent interviews and/or electronic medical record abstraction; COVID-19 vaccination was assessed through documented sources. We assessed associations between receipt of the COVID-19 vaccine and demographic and clinical factors using univariate and multivariable logistic regression and estimated adjusted odds ratios (aOR) for each factor associated with non-vaccination.

RESULTS

Among 1665 hospitalized adolescents without COVID-19, 56% were unvaccinated. Unvaccinated adolescents were younger (median age 15.1 years vs. 15.4 years, p < .01) and resided in areas with higher social vulnerability index (SVI) scores (median 0.6 vs 0.5, p < .001) than vaccinated adolescents. Residence in the Midwest [aOR 2.60 (95% CI: 1.80, 3.79)] or South [aOR 2.49 (95% CI: 1.77, 3.54)] US census regions, rarely or never receiving influenza vaccine [aOR 5.31 (95% CI: 3.81, 7.47)], and rarely or never taking precautions against COVID-19 [aOR 3.17 (95% CI: 1.94, 5.31)] were associated with non-vaccination against COVID-19.

CONCLUSIONS

Efforts to increase COVID-19 vaccination of adolescents should focus on persons with geographic, socioeconomic, and medical risk factors associated with non-vaccination.

A Comprehensive Review on the Current Vaccines and Their Efficacies to Combat SARS-CoV-2 Variants

Since the first case of Coronavirus disease (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in 2019, SARS-CoV-2 infection has affected many individuals worldwide. Eventually, some highly infectious mutants-caused by frequent genetic recombination-have been reported for SARS-CoV-2 that can potentially escape from the immune responses and induce long-term immunity, linked with a high mortality rate. In addition, several reports stated that vaccines designed for the SARS-CoV-2 wild-type variant have mixed responses against the variants of concern (VOCs) and variants of interest (VOIs) in the human population. These results advocate the designing and development of a panvaccine with the potential to neutralize all the possible emerging variants of SARS-CoV-2. In this context, recent discoveries suggest the design of SARS-CoV-2 panvaccines using nanotechnology, siRNA, antibodies or CRISPR-Cas platforms. Thereof, the present comprehensive review summarizes the current vaccine design approaches against SARS-CoV-2 infection, the role of genetic mutations in the emergence of new viral variants, the efficacy of existing vaccines in limiting the infection of emerging SARS-CoV-2 variants, and efforts or challenges in designing SARS panvaccines.

Clinician perspectives on pediatric COVID-19 vaccination: A qualitative study in central and western, Massachusetts

We explored perspectives of clinicians in central and western Massachusetts about efforts to vaccinate pediatric patients against COVID-19 as well as best practices and challenges for vaccine delivery. We conducted semi-structured qualitative interviews (n = 16) with family practice and pediatric clinicians between late October and early December 2021. Our interviews addressed: process for vaccination and vaccine promotion, parental receptivity to COVID-19 vaccination, receptivity to other pediatric vaccines, resources needed to support vaccine promotion, and best practices developed to encourage hesitant parents. Using a multi-prong recruitment strategy we invited clinicians to participate in telephone interviews, which were audio-recorded and transcribed. We used rapid qualitative analysis to produce summary templates for each interview which were ultimately combined into a matrix summary. The majority of participants (n = 10) were offering the vaccine in their own clinics, while the remainder cited challenges related to staffing, logistics, and space that prevented them from offering the vaccine. Clinicians reported parents fall into three groups: vaccine-accepting, hesitant but potentially accepting, and refusers. Strategies they identified that worked to encourage hesitant parents were sharing personal vaccine stories, acknowledging parents' fears about the vaccine, and being persistent with the most hesitant parents. Yet resources are needed including educational materials and training in how to have these conversations. While challenges related to staffing and space will be difficult to overcome for clinics to be able to offer vaccination on-site, our results highlight the importance of developing effective messaging strategies and training clinicians in how to integrate them into routine practice.

Public Perception of SARS-CoV-2 Vaccines Among Psoriasis Patients in Social Media: Content, Sentiment, and Engagement Analysis

Background

Psoriasis patients may seek information about the SARS-CoV-2 vaccine and their disease from social media platforms. Analyses of social media interactions may help guide dermatologists' educational efforts during this pandemic.

Objectives

This study analyzes social media interactions among patients with psoriasis and psoriatic arthritis regarding the SARS-CoV-2 vaccine to determine the misinformation circulating and the apprehension to receiving the vaccine.

Methods

Publicly accessible Facebook and Reddit groups regarding psoriasis and psoriatic arthritis were identified. Posts uploaded between March 1, 2021 and July 31, 2021 which contained information about the SARS-CoV-2 vaccine were extracted. First-order themes, sub-themes, sentiment scores and engagement scores were assigned to each post.

Results

345 posts within the first-order theme of vaccination decision and 1379 posts within the first-order theme of vaccine reaction were analyzed. Within vaccination decision, common sub-themes for refusing the vaccine include fear of psoriasis flare up, vaccine is experimental, vaccine is unnecessary, vaccine is dangerous, and concern for reaction/vaccine efficacy while on psoriasis medications. 41.4% of posts contained positive sentiment; whereas, 38.3% contained negative sentiment. Within vaccine reaction, common sub-themes identified were no change to psoriasis, skin/joint flare up, skin flare up attributed specifically to stopping psoriasis medications, skin/joint improvement, and skin flare up but vaccine was worth it. 77.8% of posts contained positive sentiment; whereas, 6.2% contained negative sentiment.

Conclusions

Our study identified common SARS-CoV-2 vaccine concerns within the psoriasis community which should be used to guide educational efforts.

Parents' perspective on COVID-19 vaccine in children 6 months through 4 years: a cross-sectional study from Northwest Wisconsin

Vaccination is critical to control the ongoing COVID-19 pandemic, but despite the availability of safe and effective vaccine in children over 5 years, vaccination rates remain low. There is paucity of data about vaccine acceptance and factors influencing parents' hesitancy about the COVID-19 vaccine for young children.

AIMS AND OBJECTIVES

To estimate vaccine acceptance by parents of children 6 months through 4 years, and to evaluate the factors influencing vaccine hesitancy.

METHODS

Electronic survey was sent to parents of children 6 months through 4 years through an online portal account at Mayo Clinic Health System, Northwest-Wisconsin. Data were captured via Research Electronic Data Capture secured data collection software. Bivariate and multivariate regression was used to determine most pertinent factors influencing parents' decisions against the outcome, 'Intent to Vaccinate'.

RESULTS

39.7% of the parents were 'very likely' or 'somewhat likely' to vaccinate their children once the vaccine became available, while 49.8% were not likely or highly unlikely to vaccinate. Routine childhood vaccination, receiving seasonal influenza vaccine, parents' perception of COVID-19 severity in children and safety and effectiveness of the vaccine were all associated with more vaccine acceptance. 71.4% of parents who will likely not vaccinate their children indicated that they are unlikely to change their decision. The need for more research on the vaccine and more information from the PCP office were the most common reasons behind the vaccine decision-making.

CONCLUSIONS

Vaccine hesitancy remains a major issue regarding uptake of the upcoming COVID-19 vaccine. Strong and clear evidence-based recommendations from primary care provider and more information from trusted websites such as Centers for Disease Control and Prevention can decrease vaccine hesitancy in parents. Further research targeted at understanding beliefs and perspectives of parents from different demographics can assist policy-makers in implementing measures to improve vaccination rates in children and tailor our dialogue to match the needs of our patients and families.

The propensity of fomite spread of SARS-CoV-2 virus through produce supply chain

BACKGROUND

The global community has battled the spread of SAR-CoV-2 for almost 2 years, and the projection is that the virus may be recurrent like the seasonal flu. The SARS-CoV-2 pandemic disrupted activities within the food supply chain that cost billions of dollars globally. This has heightened concerns about fomite spread of the virus through surfaces. There is an urgent need to understand the risk portends by this virus along the produce supply chain with conditions (low temperature and high relative humidity) conducive to extended survival of the virus.

MAIN BODY

Pre-dating SARS-CoV-2 are other types of coronaviruses that had lower infection and mortality rates. There are some similarities between the former and the new coronavirus, especially with regards to transmission modes and their survivability on surfaces. There is evidence of other coronaviruses' survival on surfaces for weeks. Currently, there are limited evidence-based studies to enlighten us on how the virus is transmitted within the produce supply chain. A few studies claim that the virus could spread through the cold supply chains. However, these are not sufficient to make a conclusive inference about the deadly SARS-CoV-2.

CONCLUSIONS

This paper provides a succinct review of the literature on current understanding of the transmission, survivability, and risk SARS-CoV-2 portend to humans within the produce supply chain and calls for more evidence-based research to allay or alert us of the potential risk of fomite transmission of SARS-CoV-2. The paper also highlights examples of conventional and novel non-thermal inactivation and sanitation methods applicable to this type of virus.

Maternal COVID-19 Vaccine May Reduce the Risk of MIS-C in Infants: A Narrative Review

COVID-19 infection in the pediatric population usually leads to a mild illness; however, a rare but serious complication of MIS-C has been seen in children. MIS-C usually presents 2–4 weeks after COVID-19 infection or exposure, and rare reports have been documented in neonates. Vaccinations for COVID-19 have been approved for children aged 6 months and above in the United States, and recent reports suggest significantly low prevalence and risk of complications of Multi-organ Inflammatory Syndrome (MIS-C) in vaccinated children compared to unvaccinated children. Vaccinations for COVID-19 are safe and recommended during pregnancy and prevent severe maternal morbidity and adverse birth outcomes. Evidence from other vaccine-preventable diseases suggests that through passive transplacental antibody transfer, maternal vaccinations are protective against infections in infants during the first 6 months of life. Various studies have demonstrated that maternal COVID-19 vaccination is associated with the presence of anti-spike protein antibodies in infants, persisting even at 6 months of age. Further, completion of a 2-dose primary mRNA COVID-19 vaccination series during pregnancy is associated with reduced risk for COVID-19–associated hospitalization among infants aged 6 months or less. Therefore, it can be hypothesized that maternal COVID-19 vaccination can reduce the risk of and severity of MIS-C in infants. In this article, we review the literature to support this hypothesis.

Analysis of School-Level Vaccination Rates by Race, Ethnicity, and Geography in New York City

This cross-sectional study of New York City school data examines differences in COVID-19 vaccination rates by race, ethnicity, and borough.

Association of Severe Acute Respiratory Syndrome Coronavirus 2 Vaccination or a Prior Positive Test Result in Adolescents during the Delta Variant Surge in Kentucky

In a cross-sectional study of 89 736 adolescents in Kentucky, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) vaccination provided an estimated protection against infection of 81% when the highly transmissible Delta variant was predominant. Vaccination provided added benefit to those with a history of prior infection. These findings support the recommendation that all adolescents receive SARS-CoV-2 vaccination.

SARS-CoV-2 Infection: Host Response, Immunity, and Therapeutic Targets

Coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection has resulted in a global pandemic with severe socioeconomic effects. Immunopathogenesis of COVID-19 leads to acute respiratory distress syndrome (ARDS) and organ failure. Binding of SARS-CoV-2 spike protein to human angiotensin-converting enzyme 2 (hACE2) on bronchiolar and alveolar epithelial cells triggers host inflammatory pathways that lead to pathophysiological changes. Proinflammatory cytokines and type I interferon (IFN) signaling in alveolar epithelial cells counter barrier disruption, modulate host innate immune response to induce chemotaxis, and initiate the resolution of inflammation. Here, we discuss experimental models to study SARS-CoV-2 infection, molecular pathways involved in SARS-CoV-2-induced inflammation, and viral hijacking of anti-inflammatory pathways, such as delayed type-I IFN response. Mechanisms of alveolar adaptation to hypoxia, adenosinergic signaling, and regulatory microRNAs are discussed as potential therapeutic targets for COVID-19.

Effectiveness Associated With BNT162b2 Vaccine Against Emergency Department and Urgent Care Encounters for Delta and Omicron SARS-CoV-2 Infection Among Adolescents Aged 12 to 17 Years

Importance

Data about the duration of protection of 2 and 3 doses of BNT162b2 in children and adolescents are needed to help inform recommendations for boosters in this age group.

Objective

To evaluate vaccine effectiveness (VE) and durability associated with 2 doses of BNT162b2 against Delta- and Omicron-related emergency department (ED) and urgent care (UC) encounters among adolescents aged 12 to 17 years and to estimate VE associated with 3 doses against these same outcomes.

Design, Setting, and Participants

This test-negative case-control study was conducted at Kaiser Permanente Southern California, an integrated health care system using electronic health records in the US. Participants included Kaiser Permanente Southern California members ages 12 to 17 years with an ED or UC encounter from November 1, 2021, through March 18, 2022, for acute respiratory infection who were tested for SARS-CoV-2 via a reverse transction-polymerase chain reaction test. Analyses were conducted from March 21 to June 22, 2022.

Exposures

BNT162b2 vaccination status ascertained from electronic health records and state registry data.

Main Outcomes and Measures

The main outcome was VE associated with BNT162b2 against ED and UC encounters related to Delta or Omicron variant SARS-CoV-2 infection.

Results

Analyses were conducted among 3168 adolescents, including 1004 with ED visits and 2164 with UC visits. Median (IQR) age was 15 (13-16) years, and 1461 (46.1%) were boys. In adjusted analyses, VE associated with 2 doses of BNT162b2 against ED or UC encounters was highest within the first 2 months for both Delta (89% [95% CI, 69% to 96%]) and Omicron (73% [95% CI, 54% to 84%]) variants but waned to 49% (95% CI, 27% to 65%) for the Delta variant and 16% (95% CI, -7% to 34%) for the Omicron variant at 6 months and beyond. A third dose of BNT162b2 was associated with improved protection against the Omicron variant (87% [95% CI, 72% to 94%]) after a median (IQR) of 19 (9-32) days after dose 3.

Conclusions and Relevance

These findings suggest that 2 doses of the BNT162b2 COVID-19 vaccine were associated with high levels of protection against ED and UC encounters related to the Delta and Omicron variants of SARS-CoV-2 in the first few months after vaccination. However, effectiveness waned over time, especially against Omicron. A third dose of BNT162b2 was associated with improved protection against Omicron beyond that seen initially after 2 doses, underscoring the importance of boosters for adolescents aged 12 to 17 years.

Immunologic response, Efficacy, and Safety of Vaccines against COVID-19 Infection in Healthy and immunosuppressed Children and Adolescents Aged 2 - 21 years old: A Systematic Review and Meta-analysis

Children and adolescents form a large proportion of societies and play an important role in the transmission of COVID-19. On the other hand, their education, mental and physical wellness, and safety are compromised which makes vaccination a crucial step to return to normal life. In the current systematic review, the COVID-19 vaccination was evaluated in a total of 50,148 children and adolescents in 22 published studies and 5,279 participants in two ongoing clinical trials. The study was registered in the PROSPERO with the ID# CRD42022303615. Data were collected about multiple vaccines including BNT162b2 (Pfizer), mRNA-1273 (Moderna), JNJ-78436735 (Johnson and Johnson), CoronaVac (Sinovac), BBIBP-CorV (Sinopharm), adenovirus type-5-vectored vaccine, ZyCov-D, and BBV152 (COVAXIN). The immune response and efficacy of such vaccines were 96% - 100% in healthy children and adolescents and were also acceptable in those with underlying diseases and suppressed immune systems. The current systematic review revealed favorable safety profiles of employed vaccines in children and adolescents; however, adverse reactions such as myocarditis and myopericarditis were reported which were transient and resolved entirely. Consequently, vaccinating children and adolescents aged 2 - 21 years old is beneficial to abort the COVID-19 pandemic. Moreover, the risk-benefit assessments revealed favorable results for vaccinating children and adolescents, especially those with underlying diseases and immunosuppressed conditions, alongside adults to prevent transmission, severe infection, negative outcomes, and new variants formation. Also, according to the meta-analysis, the efficacy and immune response of vaccines after the first and second doses were 91% and 92%, respectively. Meanwhile, overall immune response for all vaccines was 95% and 91% for Pfizer vaccine.

Update on COVID-19 vaccination in pediatric solid organ transplant recipients

BACKGROUND

COVID-19 vaccination has been successful in decreasing rates of SARS-CoV-2 infection in areas with high vaccine uptake. Cases of breakthrough SARS-CoV-2 infection remain infrequent among immunocompetent vaccine recipients who are protected from severe COVID-19. Robust data demonstrate the safety, immunogenicity, and effectiveness of several COVID-19 vaccine formulations. Importantly, Pfizer-BioNTech BNT162b2 mRNA COVID-19 vaccine studies have now included children as young as 5 years of age with safety, immunogenicity, and effectiveness data publicly available. In the United States, emergency use authorization by the Federal Drug Administration and approval from the Centers for Disease Control/Advisory Committee on Immunization Practices have been provided for the 5- to 11-year-old age group.

METHODS

Members of the International Pediatric Transplant Association (IPTA) provide an updated review of current COVID-19 vaccine data with focus on pediatric solid organ transplant (SOT)-specific issues.

RESULTS

This review provides an overview of current COVID-19 immunogenicity, safety, and efficacy data from key studies, with focus on data of importance to pediatric SOT recipients. Continued paucity of data in the setting of pediatric transplantation remains a challenge.

CONCLUSIONS

Further studies of COVID-19 vaccination in pediatric SOT recipients are needed to better understand post-vaccine COVID-19 T-cell and antibody kinetics and determine the optimal vaccine schedule. Increased COVID-19 vaccine acceptability, uptake, and worldwide availability are needed to limit the risk that COVID-19 poses to pediatric solid organ transplant recipients.

Post-vaccination infection rates and modification of COVID-19 symptoms in vaccinated UK school-aged children and adolescents: A prospective longitudinal cohort study

BACKGROUND

We aimed to explore the effectiveness of one-dose BNT162b2 vaccination upon SARS-CoV-2 infection, its effect on COVID-19 presentation, and post-vaccination symptoms in children and adolescents (CA) in the UK during periods of Delta and Omicron variant predominance.

METHODS

In this prospective longitudinal cohort study, we analysed data from 115,775 CA aged 12-17 years, proxy-reported through the Covid Symptom Study (CSS) smartphone application. We calculated post-vaccination infection risk after one dose of BNT162b2, and described the illness profile of CA with post-vaccination SARS-CoV-2 infection, compared to unvaccinated CA, and post-vaccination side-effects.

FINDINGS

Between August 5, 2021 and February 14, 2022, 25,971 UK CA aged 12-17 years received one dose of BNT162b2 vaccine. The probability of testing positive for infection diverged soon after vaccination, and was lower in CA with prior SARS-CoV-2 infection. Vaccination reduced proxy-reported infection risk (-80·4% (95% CI -0·82 -0·78) and -53·7% (95% CI -0·62 -0·43) at 14-30 days with Delta and Omicron variants respectively, and -61·5% (95% CI -0·74 -0·44) and -63·7% (95% CI -0·68 -0.59) after 61-90 days). Vaccinated CA who contracted SARS-CoV-2 during the Delta period had milder disease than unvaccinated CA; during the Omicron period this was only evident in children aged 12-15 years. Overall disease profile was similar in both vaccinated and unvaccinated CA. Post-vaccination local side-effects were common, systemic side-effects were uncommon, and both resolved within few days (3 days in most cases).

INTERPRETATION

One dose of BNT162b2 vaccine reduced risk of SARS-CoV-2 infection for at least 90 days in CA aged 12-17 years. Vaccine protection varied for SARS-CoV-2 variant type (lower for Omicron than Delta variant), and was enhanced by pre-vaccination SARS-CoV-2 infection. Severity of COVID-19 presentation after vaccination was generally milder, although unvaccinated CA also had generally mild disease. Overall, vaccination was well-tolerated.

FUNDING

UK Government Department of Health and Social Care, Chronic Disease Research Foundation, The Wellcome Trust, UK Engineering and Physical Sciences Research Council, UK Research and Innovation London Medical Imaging & Artificial Intelligence Centre for Value Based Healthcare, UK National Institute for Health Research, UK Medical Research Council, British Heart Foundation and Alzheimer's Society, and ZOE Limited.

Children, adolescents, and young adults hospitalized with COVID-19 and diabetes in summer 2021

INTRODUCTION

More information is needed to understand the clinical epidemiology of children and young adults hospitalized with diabetes and COVID-19. We describe the demographic and clinical characteristics of patients <21 years old hospitalized with COVID-19 and either Type 1 or Type 2 Diabetes Mellitus (T1DM or T2DM) during peak incidence of SARS-CoV-2 infection with the B.1.617.2 (Delta) variant.

METHODS

This is a descriptive sub-analysis of a retrospective chart review of patients aged <21 years hospitalized with COVID-19 in six US children's hospitals during July-August 2021. Patients with COVID-19 and either newly diagnosed or known T1DM or T2DM were described using originally collected data and diabetes-related data specifically collected on these patients.

RESULTS

Of the 58 patients hospitalized with COVID-19 and diabetes, 34 had T1DM and 24 had T2DM. Of those with T1DM and T2DM, 26% (9/34) and 33% (8/24), respectively, were newly diagnosed. Among those >12 years old and eligible for COVID-19 vaccination, 93% were unvaccinated (42/45). Among patients with T1DM, 88% had diabetic ketoacidosis (DKA) and 6% had COVID-19 pneumonia; of those with T2DM, 46% had DKA and 58% had COVID-19 pneumonia. Of those with T1DM or T2DM, 59% and 46%, respectively, required ICU admission.

CONCLUSION

Our findings highlight the importance of considering diabetes in the evaluation of children and young adults presenting with COVID-19; the challenges of managing young patients who present with both COVID-19 and diabetes, particularly T2DM; and the importance of preventive actions like COVID-19 vaccination to prevent severe illness among those eligible with both COVID-19 and diabetes.

Maternal Vaccination and Risk of Hospitalization for Covid-19 among Infants

BACKGROUND

Infants younger than 6 months of age are at high risk for complications of coronavirus disease 2019 (Covid-19) and are not eligible for vaccination. Transplacental transfer of antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) after maternal Covid-19 vaccination may confer protection against Covid-19 in infants.

METHODS

We used a case-control test-negative design to assess the effectiveness of maternal vaccination during pregnancy against hospitalization for Covid-19 among infants younger than 6 months of age. Between July 1, 2021, and March 8, 2022, we enrolled infants hospitalized for Covid-19 (case infants) and infants hospitalized without Covid-19 (control infants) at 30 hospitals in 22 states. We estimated vaccine effectiveness by comparing the odds of full maternal vaccination (two doses of mRNA vaccine) among case infants and control infants during circulation of the B.1.617.2 (delta) variant (July 1, 2021, to December 18, 2021) and the B.1.1.259 (omicron) variant (December 19, 2021, to March 8, 2022).

RESULTS

A total of 537 case infants (181 of whom had been admitted to a hospital during the delta period and 356 during the omicron period; median age, 2 months) and 512 control infants were enrolled and included in the analyses; 16% of the case infants and 29% of the control infants had been born to mothers who had been fully vaccinated against Covid-19 during pregnancy. Among the case infants, 113 (21%) received intensive care (64 [12%] received mechanical ventilation or vasoactive infusions). Two case infants died from Covid-19; neither infant's mother had been vaccinated during pregnancy. The effectiveness of maternal vaccination against hospitalization for Covid-19 among infants was 52% (95% confidence interval [CI], 33 to 65) overall, 80% (95% CI, 60 to 90) during the delta period, and 38% (95% CI, 8 to 58) during the omicron period. Effectiveness was 69% (95% CI, 50 to 80) when maternal vaccination occurred after 20 weeks of pregnancy and 38% (95% CI, 3 to 60) during the first 20 weeks of pregnancy.

CONCLUSIONS

Maternal vaccination with two doses of mRNA vaccine was associated with a reduced risk of hospitalization for Covid-19, including for critical illness, among infants younger than 6 months of age. (Funded by the Centers for Disease Control and Prevention.).

COVID-19 in children: epidemic issues and candidate vaccines

A large-scale vaccination of coronavirus disease-19 (COVID-19) in adults has been conducted for nearly a year, and there is a growing recognition that immunization for children is also essential. It has been months since emergency use of pediatric COVID-19 vaccine was approved, we reviewed the prevalence and transmission of COVID-19 in children. The prevalence of COVID-19 in children is reduced due to vaccination even in a Delta prevalent period, so an increase in the vaccination rate is needed in children. Although the precise role of children in the transmission requires more research to uncover, they likely played a significant role, according to the available literature. We also described four candidate COVID-19 vaccines for children on their safety and immunogenicity and the impact of severe acute respiratory syndrome coronavirus 2 variants on childhood vaccination. Safety issues on pediatric vaccines post-approval, like adverse events following immunization and adverse events of special interest require studies on long-term and effective regulatory mechanisms.

Immunogenicity of BNT162b2 Vaccination against SARS-CoV-2 Omicron Variant and Attitudes toward a COVID-19 Booster Dose among Healthy Thai Adolescents

Despite the BNT162b2 vaccination coverage, rapid transmission of Omicron SARS-CoV-2 has occurred, which is suspected to be due to the immune escape of the variant or waning vaccine efficacy of multiple BNT162b2 vaccination doses. Our study aims to compare immunogenicity against Omicron prior to and post a booster dose of BNT162b2 in healthy adolescents, and to evaluate their attitudes toward booster dose vaccination. A cross sectional study was conducted among healthy adolescents aged 12–17 who received two doses of BNT162b2 more than 5 months ago. Participants and their guardians performed self-reported questionnaires regarding reasons for receiving the booster. A 30 ug booster dose of BNT162b2 was offered. Immunogenicity was evaluated by a surrogate virus neutralization test (sVNT) against the Omicron variant, and anti-spike-receptor-binding-domain IgG (anti-S-RBD IgG) taken pre-booster and 14-days post-booster. From March to April 2022, 120 healthy Thai adolescents with a median age of 15 years (IQR 14–16) were enrolled. sVNT against Omicron pre- and post-booster had 11.9 (95%CI 0–23.9) and 94.3 (90.6–97.4) % inhibition. Geometric means (GMs) of anti-S-RBD IgG increased from 837 (728, 953) to 3041 (2893, 3229) BAU/mL. Major reasons to receive the booster vaccination were perceived as vaccine efficacy, reduced risk of spreading infection to family, and safe resumption of social activities. A booster dose of BNT162b2 elicits high immunogenicity against the Omicron variant. Motivation for receiving booster doses is to reduce risk of infection.

The Clinical and Genomic Epidemiology of Rhinovirus in Homeless Shelters-King County, Washington

BACKGROUND

Rhinovirus (RV) is a common cause of respiratory illness in all people, including those experiencing homelessness. RV epidemiology in homeless shelters is unknown.

METHODS

We analyzed data from a cross-sectional homeless shelter study in King County, Washington, October 2019-May 2021. Shelter residents or guardians aged ≥3 months reporting acute respiratory illness completed questionnaires and submitted nasal swabs. After 1 April 2020, enrollment expanded to residents and staff regardless of symptoms. Samples were tested by multiplex RT-PCR for respiratory viruses. A subset of RV-positive samples was sequenced.

RESULTS

There were 1066 RV-positive samples with RV present every month of the study period. RV was the most common virus before and during the coronavirus disease 2019 (COVID-19) pandemic (43% and 77% of virus-positive samples, respectively). Participants from family shelters had the highest prevalence of RV. Among 131 sequenced samples, 33 RV serotypes were identified with each serotype detected for ≤4 months.

CONCLUSIONS

RV infections persisted through community mitigation measures and were most prevalent in shelters housing families. Sequencing showed a diversity of circulating RV serotypes, each detected over short periods of time. Community-based surveillance in congregate settings is important to characterize respiratory viral infections during and after the COVID-19 pandemic.

CLINICAL TRIALS REGISTRATION

NCT04141917.

Safety and efficacy of COVID-19 vaccines in children and adolescents: A systematic review of randomized controlled trials

To systematically review and synthesize the safety and efficacy of coronavirus disease‐2019 (COVID‐19) vaccines in children and adolescents. PubMed, EMBASE, Web of Science, Cochrane Library databases, the International Clinical Trials Registry Platform (ICTRP), the Chinese Clinical Trials Registry (ChiCTR), and ClinicalTrials.gov website were searched to collect accessible randomized controlled trials (RCTs) about the safety and efficacy of human COVID‐19 vaccines in children and adolescents until May 1, 2022. Three steps, including duplicate removal, title and abstract screening, and full‐text review, were used to screen the studies. The Cochrane risk‐of‐bias tool for RCTs was used to assess the bias risk of the included studies. Microsoft Excel 16.57 (2021) software was used for data extraction and analysis. (PROSPERO Code No: CRD42021295422). COVID‐19 vaccines were evaluated in a total of 10 950 children and adolescents in seven published studies and over 49 530 participants in 26 ongoing randomized controlled trials. Descriptive findings of the included published studies were reported stratified by vaccine type. The overall, local, and systemic adverse events following immunization (AEFIs) reported in most trials were similar between the vaccine and placebo groups. Most of the reactions reported were mild to moderate, whereas a few were severe. The common adverse events were injection‐site pain, fever, headache, cough, fatigue, and muscle pain. Few clinical trials reported serious adverse events, but most of them were unrelated to vaccination. In terms of efficacy, the investigated messenger RNA (mRNA) vaccine was found to be 90.7%–100% efficacious in preventing COVID‐19 among children and adolescents, revealing good efficacy profiles in this age group. Among children and adolescents, the safety of current COVID‐19 vaccines is acceptable, and studies have suggested that mRNA vaccines can provide high protection against COVID‐19 infection in pediatric age groups.

Safety and immunogenicity of the ChAdOx1 nCoV-19 (AZD1222) vaccine in children aged 6-17 years: a preliminary report of COV006, a phase 2 single-blind, randomised, controlled trial

BACKGROUND

Vaccination of children and young people against SARS-CoV-2 is recommended in some countries. Scarce data have been published on immune responses induced by COVID-19 vaccines in people younger than 18 years compared with the same data that are available in adults.

METHODS

COV006 is a phase 2, single-blind, randomised, controlled trial of ChAdOx1 nCoV-19 (AZD1222) in children and adolescents at four trial sites in the UK. Healthy participants aged 6-17 years, who did not have a history of chronic respiratory conditions, laboratory-confirmed COVID-19, or previously received capsular group B meningococcal vaccine (the control), were randomly assigned to four groups (4:1:4:1) to receive two intramuscular doses of 5 × 10¹⁰ viral particles of ChAdOx1 nCoV-19 or control, 28 days or 84 days apart. Participants, clinical investigators, and the laboratory team were masked to treatment allocation. Study groups were stratified by age, and participants aged 12-17 years were enrolled before those aged 6-11 years. Due to the restrictions in the use of ChAdOx1 nCoV-19 in people younger than 30 years that were introduced during the study, only participants aged 12-17 years who were randomly assigned to the 28-day interval group had received their vaccinations at the intended interval (day 28). The remaining participants received their second dose at day 112. The primary outcome was assessment of safety and tolerability in the safety population, which included all participants who received at least one dose of the study drug. The secondary outcome was immunogenicity, which was assessed in participants who were seronegative to the nucleocapsid protein at baseline and received both prime and boost vaccine. This study is registered with ISRCTN (15638344).

FINDINGS

Between Feb 15 and April 2, 2021, 262 participants (150 [57%] participants aged 12-17 years and 112 [43%] aged 6-11 years; due to the change in the UK vaccination policy, the study terminated recruitment of the younger age group before the planned number of participants had been enrolled) were randomly assigned to receive vaccination with two doses of either ChAdOx1 nCoV-19 (n=211 [n=105 at day 28 and n=106 at day 84]) or control (n=51 [n=26 at day 28 and n=25 at day 84]). One participant in the ChAdOx1 nCoV-19 day 28 group in the younger age bracket withdrew their consent before receiving a first dose. Of the participants who received ChAdOx1 nCoV-19, 169 (80%) of 210 participants reported at least one solicited local or systemic adverse event up to 7 days following the first dose, and 146 (76%) of 193 participants following the second dose. No serious adverse events related to ChAdOx1 nCoV-19 administration were recorded by the data cutoff date on Oct 28, 2021. Of the participants who received at least one dose of ChAdOx1 nCoV-19, there were 128 unsolicited adverse events up to 28 days after vaccination reported by 83 (40%) of 210 participants. One participant aged 6-11 years receiving ChAdOx1 nCoV-19 reported a grade 4 fever of 40·2°C on day 1 following first vaccination, which resolved within 24 h. Pain and tenderness were the most common local solicited adverse events for all the ChAdOx1 nCoV-19 and capsular group B meningococcal groups following both doses. Of the 242 participants with available serostatus data, 14 (6%) were seropositive at baseline. Serostatus data were not available for 20 (8%) of 262 participants. Among seronegative participants who received ChAdOx1 nCoV-19, anti-SARS-CoV-2 IgG and pseudoneutralising antibody titres at day 28 after the second dose were higher in participants aged 12-17 years with a longer interval between doses (geometric means of 73 371 arbitrary units [AU]/mL [95% CI 58 685-91 733] and 299 half-maximal inhibitory concentration [IC₅₀; 95% CI 230-390]) compared with those aged 12-17 years who received their vaccines 28 days apart (43 280 AU/mL [95% CI 35 852-52 246] and 150 IC₅₀ [95% CI 116-194]). Humoral responses were higher in those aged 6-11 years than in those aged 12-17 years receiving their second dose at the same 112-day interval (geometric mean ratios 1·48 [95% CI 1·07-2·07] for anti-SARS-CoV-2 IgG and 2·96 [1·89-4·62] for pseudoneutralising antibody titres). Cellular responses peaked after a first dose of ChAdOx1 nCoV-19 across all age and interval groups and remained above baseline after a second vaccination.

INTERPRETATION

ChAdOx1 nCoV-19 is well tolerated and immunogenic in children aged 6-17 years, inducing concentrations of antibody that are similar to those associated with high efficacy in phase 3 studies in adults. No safety concerns were raised in this trial.

FUNDING

AstraZeneca and the UK Department of Health and Social Care through the UK National Institute for Health and Care Research.

Association of Trends in Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) Seroprevalence and State-Issued Nonpharmaceutical Interventions: United States, 1 August 2020 to 30 March 2021

BACKGROUND

We assess if state-issued nonpharmaceutical interventions (NPIs) are associated with reduced rates of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection as measured through anti-nucleocapsid (anti-N) seroprevalence, a proxy for cumulative prior infection that distinguishes seropositivity from vaccination.

METHODS

Monthly anti-N seroprevalence during 1 August 2020 to 30 March 2021 was estimated using a nationwide blood donor serosurvey. Using multivariable logistic regression models, we measured the association of seropositivity and state-issued, county-specific NPIs for mask mandates, gathering bans, and bar closures.

RESULTS

Compared with individuals living in a county with all three NPIs in place, the odds of having anti-N antibodies were 2.2 (95% confidence interval [CI]: 2.0-2.3) times higher for people living in a county that did not have any of the 3 NPIs, 1.6 (95% CI: 1.5-1.7) times higher for people living in a county that only had a mask mandate and gathering ban policy, and 1.4 (95% CI: 1.3-1.5) times higher for people living in a county that had only a mask mandate.

CONCLUSIONS

Consistent with studies assessing NPIs relative to COVID-19 incidence and mortality, the presence of NPIs were associated with lower SARS-CoV-2 seroprevalence indicating lower rates of cumulative infections. Multiple NPIs are likely more effective than single NPIs.